Field of the Invention
The present invention relates to a compressor for compressing a gas.
Description of the Related Art
A reciprocation type multistage compressor has been conventionally known. For example, JP2014-020284 A discloses a compressor, which comprises a low-stage side compression part and a high-stage side compression part for further compressing a gas compressed in the low-stage side compression part. The low-stage side compression part comprises a first cylinder having a first compression chamber and a first piston for compressing a gas in the first compression chamber. The high-stage side compression part comprises a second cylinder having a second compression chamber, a second piston for compressing a gas in the second compression chamber, and a plurality of piston rings fixed to the second piston.
In a reciprocation type multistage compressor, having a plurality of compression chambers formed in a cylinder, there is a difficulty in processing if a cylinder is to be formed from a single member. To circumvent this, it is considered to form a cylinder from a plurality of divided bodies.
In order to form a cylinder from a plurality of divided bodies, however, a cylinder is assembled in consideration of variation of inner and outer diameters of the each divided body, making it difficult to minimize the width of a very small gap (hereinafter referred to as “minute gap”) formed between an outer peripheral surface of a piston and an inner peripheral surface of a cylinder at a front end side of the cylinder after assembling. It will be more difficult to minimize the width of the minute gap if a piston is also formed from a plurality of divided bodies.
On the other hand, a compression chamber, in which a high-pressure gas is introduced (hereinafter referred to as “high-pressure compression chamber”), is more likely to leak a gas as compared to a compression chamber, in which a low-pressure gas is introduced. The high-pressure compression chamber, therefore, is required to minimize the width of the minute gap mentioned above as much as possible.
The present invention was made in view of the problems described above, and it is an object thereof to minimize the width of a minute gap between a cylinder component and a pressing part.